import java.util.Scanner;

public class xx{
	public static void main(String[] args){
		Scanner in=new Scanner(System.in);
		while(in.hasNextDouble())
		{
			double x=in.nextDouble();
			double a=0,b;
			b=Double.compare(1, x);
			double c=(a+b)/2;
			while(Math.abs(Math.pow(c, c)-x)>0.00001){
				if(Math.pow(c, c)<x)
					a=c;
				else b=c;
				c=(a+b)/2.0;
			}
			System.out.printf("%.6f\n",c);
		}
		in.close();
	}
}

